You know, the regenerating FRPG version, not the fairy tale "live under the bridge and harass commuters" version - are such a wonderful idea. As far back as the 1974 version of "Monsters and Treasures" (volume 2 of the original D&D), trolls were an integral part of the monster hit list for fantasy roleplaying.
Lets take a look, for a second, at the entry from "Monsters and Treasures" for this venerated beast -
TROLLS: Thin and rubbery, loathsome Trolls are able to regenerate, so that beginning the third melee round after one is hit it will begin to repair itself. Regeneration is at the rate of 3 hit points per turn. Even totally sundered Trolls will regenerate eventually, so that unless they are burned or immersed in acid they will resume combat when they have regenerated to 6 or more hit points. In strength they are about equal to an Ogre, but as they use only their talons and fangs for weapons, only one die of damage is scored when they hit an opponent.
This early view gets some of the essentials right (in fact, it established them) - the trolls are thin and rubbery. They are loathsome. They fight with fangs and talons. They regenerate. Let me stress that last point - the troll regenerates. I think that many gamers pass this over as merely a way to extend the combat effectiveness of the troll, and forget some of the fun aspects of adventuring and dungeoneering this could lead to. But more on that later. This view of trolls is somewhat unique - for it differs from trolls in Norse legend, and it certainly differs from the image of trolls in Tolkien. Again, more on these topics later.
One of the nice things about trolls, evidently, is that their basic makeup renders them very susceptible to magical alteration. A source of strange energy is apparently all it takes to create a new subspecies of troll. In fact, from the vast domain of official 2nd Edition AD&D monster pubs, we have the following types of trolls (other than the normal troll, which is similar to He described above): Desert Troll, Fire Troll, Freshwater Troll, Giant Troll, Gray Troll, Ice Troll, Legacy Troll, Phaze Troll, Saltwater Troll, Snow Troll, Spectral Troll, Stone Troll, and the Two-Haded Troll. And this is not even getting into the multitude of Troll Types and Troll Variants espoused by v3.x of AD&D.
For the next week, I will do one troll posting a day, where I discuss attributes of the trolls, or some subvariant of troll. Here on Gaming with Chuck, it is the "Week of the Troll".